Automatic circuit-closer.



T. w. MQKBNZIE.

AUTOMATIC GIRGUIT CLOSER.

APPLIGATION FILED AUG. 25, 1909.

-%9,598. Patent ed Feb. 15, 1910.

wmvrorr 77mm 344 McKenzie WITNESSES UNTTD %TATE PATENT @FFTQE.

THOMAS W. MCKENZIE, OF HAIVIDIIOND, BRITISH COLUMBIA, CANADA.

AUTOMATIC CIBCUIT-CLOSER.

Application filed August 25,

To all whom it may concern:

Be it known that I, THOMAS lV. MCKEN- ZIE, citizen of the Dominion of Canada, residing at Hammond, in the Province of British Columbia, Canada, have invented a new and useful Automatic Circuit-Closer, of which the following is a specification.

This invention relates to a circuit closer cooperated with the lever of a telegraph key and particularly designed to automatically close the circuit within a reasonable limit of time after an operator has ceased to use his key.

lVith an ordinary telegraph key the circuit requires to be manually opened and closed, and if the operator neglects to close the circuit after he has ceased to use the key, the circuit being open at that key, cannot be used by any other station and considerable difliculty is frequently experienced in locating the source of the trouble.

In the invention which is the subject of this application this inconvenience is guarded against by providing a telegraph key with a closing contact cooperative with it, that will maintain the circuit open while the key is being used but which, within a short time after the key ceases to be used, will automatically close the circuit. This is effected by providing a contact lever that is lifted oif its contact while the key is in use, but that will gradually fall to close the contact when the key ceases to be used. This cooperative contact may be supplementary to the closing lever with which a telegraph key is usually provided, or the closing lever may be dispensed with and the automatic lever entirely relied upon as by it the circuit will be open while the key is in use, and will be automatically closed shortly after that use ceases.

Although the automatic closing device will efiect this double purpose, the essential feature of the invention lies in the provision of a contact that will automatically close the circuit when the key is not in use.

The invention is particularly described in the following specification, reference being made to the drawings by which it is accompanied, in which:

Figure 1 is an elevation and part section view showing the supplementary contact with its resistance and the relation thereto of the operating extension from the key lever, Fig. 2, a plan of a telegraph key with its supplementary contact and Fig. 3, a

Specification of Letters Patent.

1909. Serial No. 514,601.

Patented Feb. 15, 1910.

modified form of the key lever extension by which the supplementary contact is operated and the manner of connecting that contact in the circuit.

In these drawings 2 represents the lever of an ordinary telegraph key, 3 being its lever supporting frame secured to an insulated base 4.

The terminals of the external circuit which form the binding posts of the key are represented by 5 and 8, and 7 represents the insulated contact of the key lever and the contact lever that is at present used for closing the circuit when the key is not in use. This closing contact lever 10 may be retained or not, but is not necessary to efiect the closing of the circuit where my device is used as that closing is therein automatically effected.

Connections from the binding posts 5 and 8 of the external circuit are made respectively by connections 6 and 9 as at present, to the insulated contact 7 of the key, and to the metal base 3, and through it to its key lever 2.

My invention consists in providing a means for closing the circuit between the terminals 7 and 8, that is cooperative with the key lever 2, and by introducing a means for delaying this closing of the circuit so that it will not be eflected until the lapse of a reasonable length of time after the key ceases to be used. This is accomplished by the provision of a pivotally mounted contact arm 13 that is in electrical connection with one side of the circuit, which contact arm normally rests upon a contact that is in electrical connection with the other side of the circuit, and by extending the key lever as at- 15 under this contact arm 13 that it will be lifted oif its contact when the key is in use.

The fall of the contact arm 13 is delayed by providing a train of gear wheels 18, 19 with the teeth of the first wheel 18 of which a light spring or pawl 17 secured to the contact arm 13 is in engagement, so that the arm 13 being lifted by the extension 15 of the key lever when the key is depressed, it will gradually fall to close the contact when that depression is released.

Figs. 1 and 2 show the contact arm 13 as in electrical connection with the terminal 8 of the external circuit, and the contact arm normally rests upon a contact 11, as indicated by the dot and dash lines in Fig.

1, in connection with the other terminal of the circuit.

WVith this arrangement insulation 16 should be furnished on the key lever extension 15 to prevent the current passing through it.

Fig. 3 shows a modification, more readily applicable to an existing key, where the contact arm is electrically connected with the terminal 5 and normally rests upon and in electrical connection with the extension 15 of the key lever, so that the circuit is closed by connection through the contact arm 13-, the extension 15 of the key lever and through the lever and its supporting base 3 to the other terminal 8 of the circuit.

In. use, assuming the contact closing lever 10 to be opened or dispensed with entirely, the circuit being normally closed by the contact arm 13 resting upon its contact 11, as in Figs. 1 and 2, or upon thekey lever extension 15 direct as in Fig. 3.

While the key is in use the contact arm 13 is lifted off its contact to the position indicated by full lines in Fig. 1, which exaggerates the movement, in which lifting movement its pawl 17 will pass freely over the teeth of the gear or over finer ratchet teeth on a wheel introduced for the purpose if thought necessary, and when lifted the ratchet will prevent it falling freely but it will be obliged to carry with it the first wheel 18 and rotate the train of gears so that its fall will be delayed. This delay will hold the circuit open for a limited time after the key ceases to be used but thereafter the contact arm will eventually rest upon its normal support and will close the circuit.

The time of the fall may be varied by the introduction of a balance wheel and escapement 20 in the train of gears or by the provision of a heavy headed screw let movable in or out in the free end of the contact arm 13, or by both.

Having now particularly described my invention, and explained the manner of its use, I hereby declare that what I claim as new and desire to be protected by Letters Patent, is:

1. The combination with a telegraph key, of an automatic circuit closer connected in circuit with the telegraph key and mounted independent of the key, said circuit closer having a movable contact member and said key having a projection to engage said contact member to move it in one direction as the key is depressed.

2. A means for electrically closing a telegraph circuit when the operating key is not in use, said means comprising a supplemental contact arm, a contact upon which said arm normally rests to close the circuit, means cooperative with the key lever for lifting the contact arm off its contact when the key is depressed, and means for delaying the fall of the arm upon its contact.

3. A means for closing an electric telegraph circuit when the key is not in use comprising a pivotally mounted contact arm, a contact upon which said arm normally rests to close the circuit, an extension from the key lever passing under the pivotally mounted arm to lift itoif its contact when the key is depressed, and a train of gears cooperative with the contact arm that will not interfere with the lifting of the contact arm but will delay its fall.

The combination with a telegraph key, of a normally closed circuit controlling switch independent of the key, and means carried by the key to engage said switch to open said circuit when the key is depressed, and means for closing said switch a predetermined time after the key is released.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

THOMAS XV. MCKENZIE.

Witnesses ROWLAND BRITTAIN, ALEXANDER SMITH, 

